This invention relates to apparatus for operating an injection cylinder of such molding machines as a die cast machine, squeeze casting machine and a molten metal forging machine, and more particularly an injection cylinder operating apparatus in which movement of an injection cylinder and an injection sleeve in the axial direction and swinging or tilting thereof between a teeming position and an injection position are effected by a single drive means.
Heretofore, a vertical type die cast machine, such as disclosed in Ueno et al U.S. Pat. No. 4,088,178 issued on May 9, 1978 and assigned to the same assignee of this application, has been used. In the die cast machine disclosed therein, for the purpose of separating an injection sleeve at the tip of an injection cylinder away from the lower surface of a stationary metal mold or die and then tilting the injection sleeve to a teeming position, there are provided a drive means for vertically moving the injection sleeve and an independent drive means for tilting the injection sleeve together with the injection cylinder so as to perform the tilting of the injection sleeve and the docking operation in two steps. For this reason, the mechanical construction, the oil pressure circuit and the electric sequence circuit are relatively complicated. Moreover, the interval between the teeming and the starting of the injection is relatively long so that ever when the injection sleeve is electrically heated, the temperature of the molten metal tends to decrease, thus degrading the quality of the die cast products.